import java.util.*;

public class Solution {

    private class ListNode {
        int val;
        ListNode next;
        ListNode() {}
        ListNode(int val) { this.val = val; }
        ListNode(int val, ListNode next) { this.val = val; this.next = next; }
    }

    public ListNode reverseList(ListNode head) {
        if (head == null) return null;
        if (head.next == null) {
            return head;
        }
        ListNode cur = head.next;
        head.next = null;
        while (cur != null) {
            ListNode next = cur.next;
            cur.next = head;
            head = cur;
            cur = next;
        }
        return head;
    }

    public boolean isPalindrome(ListNode head) {
        if (head == null) return true;
        if (head.next == null) return true;
        //1.找到中间节点
        ListNode fast = head;
        ListNode slow = head;
        while (fast != null && fast.next != null) {
            fast = fast.next.next;
            slow = slow.next;
        }
        //2.逆置单链表
        ListNode cur = slow.next;
        slow.next = null;
        while (cur != null) {
            ListNode curNext = cur.next;
            cur.next = slow;
            slow = cur;
            cur = curNext;
        }
        fast = head;
        while (fast != slow) {
            if (fast.val != slow.val) {
                return false;
            }
            if (fast.next == slow) {
                return true;
            }
            fast = fast.next;
            slow = slow.next;
        }
        return true;
    }

    public int climbStairs(int n) {
        if (n <= 1) return 1;
        int[] dp = new int[n + 1];
        dp[0] = 1;
        dp[1] = 1;
        for (int i = 2; i <= n; i++) {
            dp[i] = dp[i - 1] + dp[i -2];
        }
        return dp[n];
    }

    public List<String> topKFrequent(String[] words, int k) {
        //1.统计每个单词出现的频率
        Map<String, Integer> map = new HashMap<>();
        for (String s : words) {
            map.put(s, map.getOrDefault(s, 0) + 1);
        }
        //2.创建比较器
        PriorityQueue<Map.Entry<String, Integer>> heap = new PriorityQueue<>(new Comparator<Map.Entry<String, Integer>>() {
            @Override
            public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {
                if (o1.getValue().compareTo(o2.getValue()) == 0) {
                    return o2.getKey().compareTo(o1.getKey());
                }
                return o1.getValue() - o2.getValue();
            }
        });
        //3.将map中的元素放入堆中
        for (Map.Entry<String, Integer> entry : map.entrySet()) {
            heap.add(entry);
            if (heap.size() > k) {
                heap.poll();
            }
        }
        //4.将堆中的元素取出，放入list中
        List<String> res = new ArrayList<>();
        while (!heap.isEmpty()) {
            res.add(heap.poll().getKey());
        }
        Collections.reverse(res);
        return res;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            String str1 = in.nextLine();
            String str2 = in.nextLine();
            func(str1, str2);
        }
    }

    /**
     *
     * @param str1 键盘没坏输入的文字
     * @param str2 实际输入的文字
     */
    private static void func(String str1, String str2) {
        Set<String> set = new HashSet<>();
        for (int i = 0; i < str2.length(); i++) {
            set.add(str2);
        }

    }

}
